Hard disks and optical disks are commonly used as data storage units. However, due to the super-paramagnetic limit of a hard disk or the laser diffraction limit of an optical disk, there is a limit to the amount of data that can be stored with these conventional devices.
In order to overcome these restrictions, a high-density data storage device using scanning probe microscopy (SPM) technology has been proposed. This data storage device includes a data storage medium, a probe tip for writing data to or reading data from the data storage medium, a probe including a cantilever on which the probe is mounted, a scanner for transferring the data storage medium, a controller for issuing commands to the storage device and controlling the operation of the storage device, and a signal processor. However, even though such a conventional storage device can store a large amount of data, it cannot be easily put to practical use because of the following problems. Since only a limited number of probe tips can be installed on the data storage medium, each probe tip must be transferred over a long distance to access or write data. For example, each probe tip may have to move through intervals of about 100 μm along x- and y-axes of the data storage medium for data to be read or written. Also, the data storage device needs a servomechanism for precisely controlling the position of the probe tip, and a unit capable of moving along a z-axis to prevent wear of the probe tip. As a result, the size of the cantilever increases, the circuit for driving the cantilever becomes more complicated, and power consumption increases. Further, a data storage device using a cantilever cannot randomly access data, and hence the access time increases.
A conventional storage device is disclosed in U.S. Patent Publication No. 2004/0047275 entitled “Storage Device and Method for Operating a Storage Device” by Cherubini, et al. The storage device described therein can neither effectively store high-density data nor randomly access the data. This is because a heater platform and probe tips are mounted on a cantilever, thus making it difficult to sufficiently increase the number of probe tips and reduce the space occupied by the cantilever.